The Lawrence Berkeley Laboratory (LBL) infiltration model was developed in 1980; since that time many simultaneous measurements of infiltration and weather have been made, allowing comparison of predictions with measured infiltration. This report presents the LBL model as it currently exists andsummarizes infiltration measurements and corresponding predictions. Thesemeasurements include both long-term and short-term data taken in houses with climates ranging from the mild San Francisco Bay area the the more extreme Midwest.
Describes a reasonably accurate method for estimating air infiltration for engineers or energy auditors who are not specially trained in infiltration research. The method requires two steps: field measurement of the building properties, and calculation of the infiltration from weather data and themeasured properties. Fan pressurization techniques are described and how to use them to measure the air tightness of the building envelope, and the procedures required to make infiltration predictions with the Lawrence Berkeley Laboratory infiltration model.
This report discusses the extension of an infiltration predicting technique to the prediction of interroom air movements. The airflow through openings is computed from the ASHRAE crack method together with a mass balance in each room. Simulta
Reviews air infiltration measurement methods, prediction models, and flow through components of buildings. Attempts to construct a device capable of measuring air flow through a building component under a given pressure difference and to investigate the existence of a coefficient which, when multiplied by the pressure difference, raised to an exponent, will yield the air flow through that component. Components were tested under differing pressure differences and the testing device was calibrated by a tracer gas technique.
Describes a new procedure for predicting the thermal comfort of people in naturally ventilated buildings. The procedure starts by obtaining, for each important wind direction, velocity ratios between points of interest inside the proposed bu
Examines the sensitivity of the predicted air infiltration rate to measured building air tightness data and the wind exposure index determined from site inspection. Presents results of air tightness tests in New Zealand houses, which indicate the range of leakage resistance for components, for solid materials (such as wall and ceiling lining materials) and for cracks separating major components such as floors and walls.
Leakage measurements of houses are common practice in many countries, partly because they are needed for predicting ventilation rates. To use the measurements in this way it is usually necessary to fit an equation to the measured leakage data, so that the data can be extended into the region of interest. At present, the power-law equation is generally chosen for the curve fit. Considers a new approach using a quadratic equation. Shows that there can be large differences between the 2 equations, so the choice of equation is important.
To simulate time-dependent interior humidity, a moisture mass balance is applied to the control volume of the envelope of a residential structure. Moisture transport mechanisms incorporated include infiltration, cooling coil condensation, int
Describes an analytical model for the prediction of ventilation rates and internal temperatures as influenced by the combined effects of heat dissipation inside industrial buildings and natural wind action. Applies this to a two span low building equipped with a natural ventilation system. Results emphasize the relative importance of thermal and dynamic variables including wind incidence, terrain roughness, and the role of the opening in the internal partition wall.